On 2024-03-07, Sreenath Vijayan <sreenath.vijayan@xxxxxxxx> wrote:
> diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst
> index 2f2e5bd440f9..8098a1b4908d 100644
> --- a/Documentation/admin-guide/sysrq.rst
> +++ b/Documentation/admin-guide/sysrq.rst
> @@ -161,6 +161,8 @@ Command Function
> will be printed to your console. (``0``, for example would make
> it so that only emergency messages like PANICs or OOPSes would
> make it to your console.)
> +
> +``R`` Replay the kernel log messages on consoles.
> =========== ===================================================================
>
> Okay, so what can I use them for?
> @@ -211,6 +213,12 @@ processes.
> "just thaw ``it(j)``" is useful if your system becomes unresponsive due to a
> frozen (probably root) filesystem via the FIFREEZE ioctl.
>
> +``Replay logs(R)`` is useful to view the kernel log messages when system is hung
> +or you are not able to use dmesg command to view the messages in printk buffer.
> +User may have to press the key combination multiple times if console system is
> +busy. If it is completely locked up, then messages won't be printed. Output
> +messages depend on current console loglevel.
> +
I recommend including a reference to SysRq [0-9] about changing the
loglevel.
> Sometimes SysRq seems to get 'stuck' after using it, what can I do?
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
> index 02217e3c916b..c4deea41a8b5 100644
> --- a/drivers/tty/sysrq.c
> +++ b/drivers/tty/sysrq.c
> @@ -450,6 +450,17 @@ static const struct sysrq_key_op sysrq_unrt_op = {
> .enable_mask = SYSRQ_ENABLE_RTNICE,
> };
>
> +static void sysrq_handle_replay_logs(u8 key)
> +{
> + console_replay_all();
> +}
> +static struct sysrq_key_op sysrq_replay_logs_op = {
> + .handler = sysrq_handle_replay_logs,
> + .help_msg = "replay-kernel-logs(R)",
> + .action_msg = "replay kernel logs on consoles",
If I do:
$ grep '\.action_msg' drivers/tty/sysrq.c
This is the only action message that begins lowercase. Please start with
a capital letter for consistency.
With the change to the action message:
Reviewed-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
